Why aren't Grindstones & Workbenches working?

I can't improve any weapons or armor on Grindstones or Workbenches. I can use tanning racks, forges, and smelters no prob, but Workbenches and Grindstones show no items (not even greyed out) in their menus. I just uninstalled, and reinstalled the game. Still doesn't work. :/

I am using the standard setup of STEP

skyrimnexus.com/downloads/file.php?id=11.#content

and used all the recommended / default setup options.

And yes they did work fine at first... at some point in the game they just stopped working though.. can't recall when exactly. A little patch or something to fix this issue would be sweet! Anyone know of one?

Additional Details:
I ended up fixing it by uninstalling all mods, and then ame, and re installing skyrim and set up only the necessary mods for STEP. The grindstones and workbenches now work again. However, I am now unable to unequip my right hand spell. Very annoying.. Luckily the hotkeys circumvent this glitch, otherwise i'd be even more pissed now.. lol

Accepted Answer

The first and most obvious suggestion is to disable your mod(s) and see if you can use the workbench/grindstone. If so, then it's a problem with STEP. If you still cannot use them, make sure you've updated to the latest patch; if an update was necessary, try again and see if that helped. If you have the most recent update and have all mods disabled and they STILL don't work... well, I'm not quite sure what to suggest. Try using different workbenches/grindstones to see if maybe it's just the location you're trying to use that's broken (probably outside Warmaiden's in Whiterun if I had to guess).